1. Field of the Invention
The present invention relates to a power-operated cutting device including a movable cutting unit. The present invention more particularly relates to power-operated cutting device including a mechanism for selectively positioning a cutting unit of the device at a predetermined position relative to a workpiece support of the device. The present invention finds application in various cutting devices including, for example power-operated miter saws, scroll saws, and drill presses.
2. Description of the Invention Background
Power-operated cutting devices such as, for example, miter saws and scroll saws, commonly include a work table or other work piece support structure and a cutting unit having a driven cutting element. In the case of a miter saw, for example, the cutting unit is a motor-driven circular saw blade. The cutting unit is movably mounted to the saw""s work table by an attachment assembly and may be pivoted downward toward the work table in an arc substantially within a vertical plane. In this way, a work piece positioned on the work table in the path of the pivoting saw blade may be cut at a substantially right angle relative to the workpiece support surface of the work table. A miter angle of the cutting unit may be adjusted by rotating the work table and the cutting unit about an axis that is substantially orthogonal to the work piece support surface. In this way, the position of the cutting unit and the orientation of the circular saw blade is changed relative to a workpiece fence against which the workpiece is supported.
One specialized type of miter saw is a dual bevel miter saw, which is a miter saw including a cutting unit that may be inclined to both leftward and rightward bevel angles relative to a vertical position of the cutting unit. The vertical position of the cutting unit is also referred to herein as the xe2x80x9c0xc2x0 bevel positionxe2x80x9d because when in that position the cutting unit is inclined neither leftward nor rightward relative to the workpiece support surface of the work table. Dual bevel miter saws typically allow the cutting unit to be inclined to bevel angles up to forty-five degrees in both the leftward and rightward directions. A bevel position locking mechanism is commonly provided on such devices. Once the cutting unit has been adjusted to the desired rightward or leftward bevel position, the locking mechanism is engaged to secure the cutting unit in place prior to executing the cut.
The vertical cutting unit position (0xc2x0 bevel position) is particularly important because it is the position at which the plane of the circular saw blade is substantially perpendicular to the workpiece support surface. A dual bevel miter saw would be cumbersome and time-consuming to operate absent an easily engageable mechanism to reliably locate and secure the cutting unit at the vertical position. For example, locating the vertical may require using a square to accurately position the plane of the circular saw blade. Also, if a cut to be made at the 0xc2x0 bevel position is accidentally made with a slight leftward or rightward bevel, it may be necessary to scrap the workpiece.
Thus, to better maximize operator efficiency in situations where the bevel position of a miter saw must be adjusted frequently between vertical and non-vertical positions, it is desirable to provide a mechanism to quickly and accurately position the cutting unit at the vertical position. Preferably, such mechanism is relatively simple to operate, is uncomplicated to manufacture, and does not require narrow manufacturing tolerances, thereby reducing manufacturing cost and, ultimately, consumer cost.
Several mechanisms are known for consistently and accurately positioning the cutting unit of a bevel miter saw at commonly used bevel positions, such as 0xc2x0 and 45xc2x0 bevel positions. However, few of these mechanisms meet each of the objectives described above. One such mechanism is described in U.S. Pat. No. 5,437,214. The ""214 patent discloses a mechanism for locating various bevel positions using movable stop members that may abut fixed stop members at various positions. The fixed stop members are located in a circumferential direction. This particular design requires numerous components and tight manufacturing tolerances, which would increase manufacturing and consumer costs.
Accordingly, a need exists for an improved mechanism for quickly and reliably locating the cutting unit of a dual bevel miter saw or other cutting device at a predetermined bevel position, such as a vertical position (0xc2x0 bevel angle). It is desirable that such mechanism is uncomplicated to operate, requires few parts to manufacture, and does not require narrow manufacturing tolerances.
In order to address the above-described need, the following invention provides a cutting device including an improved bevel stop. The cutting device may be, for example, a single or dual bevel miter saw, a scroll saw, or a drill press. The cutting device includes a base, a work table supported on the base, and a cutting unit operably connected to the work table. The work table includes a workpiece support surface, and a stop portion is mounted either directly or indirectly on the work table. A cutting unit is operably connected to the work table and is selectively rotatable about a first axis between leftward and rightward bevel positions relative to the workpiece support surface. The device also includes a rotatable stop member that is coupled to the cutting unit and travels with it as the cutting unit assumes its various positions relative to the workpiece support surface. The stop member is selectively rotatable relative to the cutting unit to selectively contact the stop portion. Preferably, the rotatable stop member is selectively rotatable relative to the cutting unit about a second axis that is substantially transverse to the first axis. Contact between the rotatable stop member and the stop portion limits rotation of the cutting unit about the first axis.
The present invention is further directed to a power-operated saw including an improved bevel stop. The power-operated saw includes a work table that is supported on the base, and a cutting unit that is pivotally coupled to the work table and selectively rotates about a first axis between leftward and rightward bevel positions relative to the workpiece support surface. A rotatable stop member is coupled to the cutting unit, and a stop portion is directly or indirectly mounted on the work table. The rotatable stop member is rotatable relative to the cutting unit about a second axis and may rotate between a first position and a second position. The stop portion prevents the cutting unit from rotating in one direction about the first axis when the rotatable stop member is in the first position. When the rotatable stop member is in the second, it is incapable of abutting the stop portion as the cutting unit rotates about the first axis.
Preferably, the stop portion is an adjustable stop member that is adjustable in position relative to the workpiece support surface. When the adjustable stop member is in a predetermined position relative to said workpiece support surface and the rotatable stop member abuts the adjustable stop member, the cutting unit is in a predetermined bevel position relative to the workpiece support surface. The predetermined position may be, for example, a vertical, 0xc2x0 bevel position.
Thus, the feature of the present invention providing selective abutment between a rotatable member mounted to the cutting unit and stop portion of the work table allows an operator to quickly, accurately, and repeatedly locate the cutting unit at a predetermined bevel position relative to the workpiece support surface. The present invention also preferably includes a bevel locking mechanism. Once the cutting unit is positioned at the predetermined bevel position, the cutting unit may be locked in position using the bevel locking mechanism. In addition to the foregoing advantages, embodiments of the present invention may include only a few parts and may be designed so as not to require close tolerances during manufacture.
Other features, objects and advantages of the present invention will become apparent from the following description of certain embodiments of the present invention.